Physiological studies on the production of the focus were conducted through laryngeal electromyography and x-ray microbeam observation of jaw movements. Perceptual studies were also conducted to examine the effect of the prosodic patterns associated with the focus in the perception of the sentence structure.1. Electromyographic study of focus production.A new method of correlation analysis between cricothyroid muscle activity and the resulting FO contour was applied to speech material varying in accentedness and focal conditions. It was found that the strong suppression of the sternohyoid muscle activity under focus. The suppression was stronger in unaccented phrases than in accented ones. The suppression and its relationship to accent can be interpreted proposed based on the notion of laryngeal state function proposed in Atkinson (1978).2. X-ray microbeam study of jaw movement in the production of focus.It has generally been acknowledged that the fundamental frequency plays a most important role in the production of the focus in Japanese. However, in recent years, it is noted that the focus also affects the segmental features. The present study revealed that the jaw opening in a given accent phrase is larger when the accent phrase is focused. Furthermore, the effect of focus was also seen in a form of the reduction of the jaw opening. Thus, the effect of focus is not a localized phenomenon.Effect of prominence on the perception of the ambiguous sentences.The effects of pitch pattern associated with focus on the syntactic ambiguity resolution of Japanese sentences were studied. The results showed that prosodic cues (pitch pattern) can influence the interpretation of a sentence even when the sentence is strongly semantically biased. The results also showed a limitation to prosodic cues. The prosodic biases alone were not sufficient to fully determine the interpretation of the sentences even when the sentences were neutrally biased semantically.